Hoping to secure a CCNP certification in routing and switching? Prepare with the best CCNP routing course in the Philippines — but, avoid attending your training sessions with rusty knowledge of routing and switching.
It’s important to remember that you are aiming for the Professional-level of this Cisco path. The instructor will assume that you have at least an Associate-level of understanding regarding relevant topics — so make sure to review your routing by exploring the overall process of it.
Exploring the IP Routing Process
When a user communicates with another user over a network or the Internet, the exchange of information from both sides is typically fast. The user receives the other’s response almost as soon as it is entered into the system. The process that the information goes through to get from one end to the other is called the IP Routing Process.
Establishing an IP Routing Process Topology
Despite its short execution time, the IP Routing Process is known for being complex and lengthy. This is why most programs of CCNP training in the Philippines reserve a few sessions for its discussion and practice.
To better understand the process, it’s important to come up with a setup and discuss its step-by-step procedure. Here’s our sample scenario’s topology.
- The communication is between PC1 and PC2.
- They are connected with a router.
- PC1 has the following specifications:
- PC2 has the following specifications:
To better assess and explain the IP routing process between these two computers, the Internet Control Message Protocol (ICMP) is a key factor to consider. It’s a TCP/IP network layer protocol that specializes in troubleshooting, management, and error message services.
Examining the Process
Here’s what will happen when PC1 communicates with PC2 using a router.
- A user implements the 192.168.1.1 command. In response, PC1 produces a packet with the support of the IP and ICMP protocols.
- With the support of the ARP protocol, the IP protocol will determine the packet’s destination network. It will do so by checking out the IP address and the subnet mask (192.168.0.1/24) of PC1.
- Once it has established that the destination is a remote network (192.168.1.0/24), the packet will be sent to the router with the gateway address of 192.168.0.100.
- To send the packet to the router, the hardware address of the router’s interface must be established. The ARP cache is checked to obtain that data.
- If the information is available, the router will provide the hardware address of the interface connected to the PC1 (Fa0/0).
- The packet will then be transferred to the Data Link layer, which will develop a frame that contains the Type filed, the Frame Check Sequence (FCS), and the hardware addresses of the destination and source.
- The Data Link layer will transfer the frame to the Physical layer, which will encode the binary bit stream into a digital signal. The digital signal will, in turn, be transferred to the local physical network.
- The router’s interface (Fa0/0) will get the signal, which will be encrypted into the binary bit stream. The interface will then set up a frame and run a CRC.
- After verifying its specifications, the router will transfer the packet to the IP protocol operating on the router.
- The packet’s destination address, which is 192.168.1.1, will be considered again on the routing table. Upon re-examining the routing table, the router will see that the 192.168.1.0 network is directly connected to the interface (Fa0/1). If the destination network is not present on the routing table, the router will discard the packet.
- The router will deposit the packet in the Fa0/1 interface’s buffer memory and develop a frame.
- PC2 will answer with its Network Interface Card’s hardware address. Now that the interface has all the details it needs to transfer the packet to its destination; the router will then send the frame to PC2.
- PC2 obtains the frame. But, that’s not the end of the process. The CRC will be calculated once the frame hits its destination. All data regarding addresses are verified.
- If the packet is an ICMP echo request (ping), PC2 will produce a new ICMP packet. It will have the PC2’s IP address as the source and the PC1’s IP address as the destination. The packet will be sent from PC2 to PC1.
Consider this as your refresher course of sorts about the IP routing process. Review the topic well before you attend your CCNP routing course in the Philippines and you can ensure that you can keep up with the instructor’s lessons and take in new information about the process a lot faster!